Controlled cutting

ABSTRACT

A platform is mounted for movement in x and y directions and carries a stylus, vibrator and a cutting tool. An operator moves the stylus along a master pattern causing the cutter to cut the master pattern in a sheet of suitable material, such as, 1/16 inch magnesium, plastic or alluminumate.

I United States Patent [191 [111 3,777,616

Mueller 1 Dec. 11, 1973 CONTROLLED CUTTING 2,539,027 1/1951 Marchant33/23 K 1746,2313 5/1956 M s a 1 308/3 R X [76] Inventor 3 3? a g gfiSouth 3,450,447 6/1969 Hzfcier 90/132 e am, ass.

[22] Filed: Primary Examiner-Gil Weidenfeld [21] Appl. NO; 210,930Attorney-Charles Hieken 33/23 C, 308/6 R [57] ABSTRACT [2;] ii utidCLf."9.6..iguinlg2l3clgliz6 A platform is mounted for movement in X and y 1g g 1 6 directions and carries a stylus, vibrator and a cutting I I 5 Rtool. An operator moves the stylus along a master pattern causing thecutter to cut the master pattern in a References Cited sheet of suitablematerial, such as, 1/16 inch magne- Wormser 33/23 C sium, plastic oralluminumate.

4 Claims, 2 Drawing [Figures CONTROLLED CUTTING BACKGROUND OF THEINVENTION The present invention relates in general to controlled cuttingand more particularly concerns improved apparatus and techniques forprecisely and repeatedly following a master pattern with a cutting tool.A typical prior art approach comprises a pantograph. A linkageinterconnects a cutting tool to a stylus so that movement of the latterproduce corresponding movements of the former. While conventionalpantographs are acceptable for relatively small cutting jobs, it isdifficult to produce large cut patterns with a pantograph.

Accordingly, it is an important object of this invention to provideimrpoved techniques for precisely following a master pattern with acutting tool.

It is a furtherobject of the invention to achieve the preceding objectrepeatedly.

It is a further object of the invention to achieve one or more of thepreceding objects with relatively large patterns. i I

It is a further object of the invention to achieve one or more of thepreceding objects while accurately following relatively complex masterpatterns including lines in various directions and curves of varyingradii.

It is a further object of the invention to achieve one or more of thepreceding objects with apparatus that is relatively easy and inexpensiveto fabricate and may be operated by relatively unskilled personnel.

SUMMARY OF THE INVENTION According to the invention, there is means formechanically interconnecting stylus means and cutting tool means so thatthe cutting tool means accurately reproduces a master pattern in acutting area in a cutting plane that is parallel to a tracing planewhere the stylus moves over the master pattern and means for vibratingat least the stylus and x-y assembly in a direction orthogonal to thecuttingand tracing planes over a small amplitude, typically five milsand smaller than the depth of the groove cut by the cutting tool. Meansare provided for supporting the assembly comprising the stylus'means andthe cutting tool means to permit slight translation in a directionorthogonal to the cutting and tracing planes and means for vibrating theassembly.

According to one aspect of the invention the assembly is supported onorthogonal x and y pairs of rods for allowing the assembly to move inthe x and y directions, respectively. The rods are of slightlyelliptical cross section with the minor axis perpendicular to thetracing and cutting planes and of the order of five mils less than themajor axis to form the inner race of support ball bearings having acircular outer race channel of inside diameter correspondingsubstantially to the major diameter of the rod plus twice a balldiameter.

Numerous other features, objects and advantages of the invention willbecome apparent from the following specification when read in connectionwith the accompanying drawing in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of anexemplary embodiment of the invention; and

FIG. 2 is a sectional view through a roller bearing exaggerating theellipticity of the rod to illustrate a feature of this bearing whichallows movement orthogonal to the tracing and cutting planes whilerestricting movement parallel to these planes.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to thedrawing and more particularly FIG. 1 thereof, there is shown aperspective view of an embodiment of the invention. As stylus 11 movesalong the lines of master pattern 12 in the tracing plane, cutting tool13 cuts out the corresponding pattern on stencil 14 in the cutting planeon table 15. Table 15 carries a pair of X rods 16 and 17. A frame 18 iscoupled to rods 16 and 17 by outer races 21, 22, 23 and 24 whichcomprise ball bearings having respec tive ones of rods 16 and 17 as theinner race.

Frame 18 carries a pair of Y rods 25 and 26 to which support platform 27is attached by outer races such as 31 and 33 comprising ball bearingswith respective ones of rods 25 and 26 forming the inner races. Platform27 hides the other pair of ball bearings and carries rotary cutting tool13 of conventional type that may be displaced through means such as acontrolled solenoid from a noncutting position above the work to acutting position with the cutting edge 35 in contact with the work whenstylus l l is displaced downward for contact with master pattern 12during tracing. The specific techniques, typically involving the use ofmicroswitches and solenoids, for accomplishing this verticaldisplacement is well known in the art and not discussed further here inorder to avoid obscuring the principles of this invention.

Platform 27 also carries a vibrator 36, that operates at Hz. Thevibrator causesthe platform 27, stylus 11 and cutting edge 35 to vibratevertically, typically at an amplitude of 5 mils, a distance less thanthe cut made in stencil, 14 so that cutting efficiency is not impairedwhile greatly enhancing the ability of the stylus and cutting tool toaccurately follow a complex master pattern 12 that may include lines invarious orientations and curves of various radii of curvature.

, To allow the vertical vibration in a plane normal to the xy tracingand cutting plane, means are provided for supporting the assembly toallow such vertical dis placement. A preferred support means whichtypifies the eight ball bearings is illustrated in the sectional view inFIG. 2 through section 2-2 of ball bearing 21. Rod 16 is shown as beingslightly smaller in diameter from top-to-bottom and from side-to-side,this distance typically being 5 mils. Yet the inside diameter of outerrace 41 is a perfect nearly complete circular sector and substantiallyequal to the sum of the major diameter of shaft 16 (from side-to-side)plus twice the diameter of one of balls 42. The invention would operateif the rods were perfectly circular and 5 mils less than the diame terrequired for a snug fit with the balls in place; however, the approachillustrated in FIG. 2 has certain advantages. It resists movement in thex-y plane and helps insure that the cutting tool will cut along a smoothline. It is more practical to cut down slightly only top and bottomportions of a perfectly circular rod designed as a snug inner race thanto turn such a rod down precisely. Reducing the top and bottom may beaccomplished by holding the rod stationary and running an abrasive orlapping wheel along the top and bottom. Turning the rod requiresrotating it in a lathe. However, it is to be understood that thespecific techniques illustrated above are by way of example forillustrating the best mode now contemplated for practicing theinvention. Numerous other approaches may be practiced within theprinciples of the invention.

For example, T bearings with the desired vertical play could be employedas supports. Numerous other supports having the desired vertical playcould be employed. The principles of the invention could also be appliedto a conventional pantograph.

The invention is especially useful in connection with the x-y platformsupport. Without the vibration in the vertical plane, it is moredifficult for the assembly to track complex master patterns. Once theassembly starts moving in the x direction, it seems to want to keepmoving in that direction, making the following of changes in linedirection difficult to follow. With the vertical vibration introduced,the assembly easily moves in any direction so that curves and changes inline direction are easily followed.

The invention is especially useful in connection with cutting stencilsin the form of relatively large box blanks that are then used as guidesto jig out die boards that may be used to accomodate cutting edges forcutting out box blanks. The box blanks may then be formed into boxes.

The actual working model of the invention shown in FIG. 1 may copy on a1:1 basis reproducing a master 30 X 36 inches while cutting throughaluminum, magnesium, plastic l/16 inch thick plate.

It is evident that those skilled in the art may now make numerousmodifications and uses of and departures from the specific embodimentsdescribed herein without departing from the inventive concepts.Consequently, the invention is to be construed as embracing each andevery novel feature and novel combination of features present in orpossessed by the apparatus and techniques herein disclosed and limitedsolely by the spirit and scope of the appended claims.

What is claimed is:

1. Apparatus for controlled cutting comprising,

stylus means for tracing a master pattern,

cutting means for cutting the copy of the pattern traced by said stylusin a cutting plane parallel to the plane of said master pattern,

means for mechanically intercoupling said stylus means and said cuttingmeans so that movements of said stylus are followed by said cuttingmeans,

means for vibrating at least said stylus means in a direction orthogonalto said cutting plane,

said stylus means, said cutting means and said means for mechanicallyintercoupling including said means for vibrating to form an assemblyvibrated by said means for vibrating,

base means,

and means for supporting said assembly on said base for permittingslight displacement thereof in a direction orthogonal to said cuttingplane,

said means for supporting comprising means for allowing relativedisplacement of said assembly in a first direction parallel to saidcutting plane and in a second direction orthogonal to said firstdirection parallel to said cutting plane and further comprismg,

at least one rod comprising the inside race of a ballbearing and ofgenerally elliptical cross section having a minor diameter orthogonal tosaid cutting plane only slightly less than its major diameter andsurrounded by an outer race of circular cross section with ballstherebetween,

the inside diameter of said outer race in the channel thereof includingsaid balls having a diameter substantially equal to the major diameterof said rod plus twice the diameter of a said ball.

2. Apparatus for controlled cutting in accordance with claim 1 whereinthere are two mutually orthogonal pairs of said rods for allowing saidstylus and cutting means to move together in said first and seconddirections.

3. Apparatus for controlled cutting comprising,

stylus means for tracing a master pattern,

cutting means for cutting the copy of the pattern traced by said stylusin a cutting plane parallel to the plane of said master pattern,

frame means for mechanically intercoupling said stylus means and saidcutting means in fixed relationship so that movements of said stylus arefollowed by said cutting means,

base means,

means for supporting said frame means on said base means to allowdisplacement of said frame means relative to said base means in firstand second orthogonal directions parallel to said cutting plane, saidmeans for supporting comprising at least one rod comprising the insiderace of a ballbearing and of generally elliptical cross section having aminor diameter orthogonal to said cutting plane only slightly less thanits major diameter and surrounded by an outer race of circular crosssection with balls therebetween, the inside diameter of said outer racein the channel thereof including said balls having a diametersubstantially equal to the major diameter of said rod plus twice thediameter of a said ball.

4. Apparatus for controlled cutting in accordance with claim 3 whereinthere are two mutually orthogonal pairs of said rods for allowing saidstylus and cutting means to move together in said first and seconddirections.

1. Apparatus for controlled cutting comprising, stylus means for tracinga master pattern, cutting means for cutting the copy of the patterntraced by said stylus in a cutting plane parallel to the plane of saidmaster pattern, means for mechanically intercoupling said stylus meansand said cutting means so that movements of said stylus are followed bysaid cutting means, means for vibrating at least said stylus means in adirection orthogonal to said cutting plane, said stylus means, saidcutting means and said means for mechanically intercoupling includingsaid means for vibrating to form an assembly vibrated by said means forvibrating, base means, and means for supporting said assembly on saidbase for permitting slight displacement thereof in a directionorthogonal to said cutting plane, said means for supporting comprisingmeans for allowing relative displacement of said assembly in a firstdirection parallel to said cutting plane and in a second directionorthogonal to said first direction parallel to said cutting plane andfurther comprising, at least one rod comprising the inside race of aball-bearing and of generally elliptical cross section having a minordiameter orthogonal to said cutting plane only slightly less than itsmajor diameter and surrounded by an outer race of circular cross sectionwith balls therebetween, the inside diameter of said outer race in thechannel thereof including said balls having a diameter substantiallyequal to the major diameter of said rod plus twice the diameter of asaid ball.
 2. Apparatus for controlled cutting in accordance with claim1 wherein there are two mutually orthogonal pairs of said rods forallowing said stylus and cutting means to move together in said firstand second directions.
 3. Apparatus for controlled cutting comprising,stylus means for tracing a master pattern, cutting means for cutting thecopy of the pattern traced by said stylus in a cutting plane parallel tothe plane of said master pattern, frame means for mechanicallyintercoupling said stylus means and said cutting means in fixedrelationship so that movements of said stylus are followed by saidcutting means, base means, means for supporting said frame means on saidbase means to allow displacement of said frame means relative to saidbase means in first and second orthogonal directions parallel to saidcutting plane, said means for supporting comprisIng at least one rodcomprising the inside race of a ballbearing and of generally ellipticalcross section having a minor diameter orthogonal to said cutting planeonly slightly less than its major diameter and surrounded by an outerrace of circular cross section with balls therebetween, the insidediameter of said outer race in the channel thereof including said ballshaving a diameter substantially equal to the major diameter of said rodplus twice the diameter of a said ball.
 4. Apparatus for controlledcutting in accordance with claim 3 wherein there are two mutuallyorthogonal pairs of said rods for allowing said stylus and cutting meansto move together in said first and second directions.